#include<iostream>
#include<algorithm>
using namespace std;
typedef long long LL;
const int N = 5e5 + 10;
LL arr[N];
int n;
int main()
{
	bool flag = 1;
	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> arr[i];
		if (arr[i] == 0) {
			flag = 0;
		}
	}
	if (!flag) {
		cout << "NO" << endl;
		return 0;
	}
	sort(arr, arr + n);
	//int k = 0;
	//for (int i = 0; i < n; i++) {
	//	if (!i || arr[i] != arr[i - 1]) {
	//		arr[k++] = arr[i];
	//	}
	//}
	//if (k == 2 && arr[0] + arr[1] == 0) {
	//	flag = 0;
	//}
	for (int i = 0; i < n; i++) {
		LL k = arr[i] + arr[i + 1];
		if (k == 0) {
			flag = 0;
		}
	}
	if (flag) {
		cout << "YES" << endl;
	}
	else {
		cout << "NO" << endl;
	}
	return 0;
}